Something to fill crack between tread and riser

[Joseph Skoler]

I'm restoring a 100 year staircase and there is varying widths of openings between the inside of the treads and the vertical risers between them.

The treads will be stained and poly'd, the risers painted.

I think I need a filler that will be flexible, because each step will cause at least a tiny bit of flex or movement.

Does anyone have a recommendation for what to use?

I've been hearing great things about Lexel caulk, for example.

Thank you,

Joseph

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[Dwayne Watt]

Could you better attach a small cove or quarter round molding on each step and let the motion occur? I don't see a flexible caulk type of filler looking good or lasting very well. However, I am sure there are other folks better versed on that sort of material than me.

[Joseph Skoler]

Thank you for the help!

I thought about molding, but (a) the treads are already not so deep (I think the run is about 9" or so) so I don't want to lose any depth and (b) it'll be continuously kicked and I'm concerned won't last very long.

But, I don't know of a better solution.

[Steve Rozmiarek]

Try to close the gap. You may be able to push or hammer the tread back where it belongs, or get underneath it and use a few screws to pull the riser to the tread. Don't use caulk or lexal on poly stairs, it'll look silly.

[Jim Becker]

Steve's recommendation is always the first thing to try..fix the stairs.

Consider adding a thin "thick veneer" facing to the risers....25" if it will work to close the gap. Dont put it behind the stair treads...just down to the top of them. You don't materially affect the stair metrics with that thin material and it will look far better than any kind of filler. Obviously, use the same species and grain characteristics as the stairs for visual compatibility after you are done with your finishing work. If you have access to the backside, you may be able to attach material to the back of the treads as an alternative.

[Richard Coers]

The problem is not the crack, it's seasonal wood movement. Surely that crack gets smaller in the summer. Any type of filler or caulk has to be able to absorb movement in two directions. If you don't like the idea of a cove or bead, how about an 1/8" thick shoe molding pinned to the riser.

[Bryan Hall]

Is removing the treads and risers out of the question? If not, I'd remove them, extend the risers, and then mate the risers to the treads like usual for a seamless finish.

[Rob Luter]

I'd remove the treads and replace them with oak treads that are properly sized. Pine treads are intended for carpet.

[Lisa Starr]

Your stairs appear to be made like the ones in our home, though ours are much older. If you have access to the underside, your need to check the riser shims. Our stairway has dados for the riser that fit somewhat loosely. After the riser was in place, shims were placed in the dado to push the riser tight to the tread. I've had to tighten up some of ours.

[George Yetka]

I would go to a shoe moulding or something with a thinner profile than 1/4 round. I would assume you could get something/make something with an ultra thin depth and attach it to the riser.

[Mark Wooden]

Someone already filled the gaps around the treads and risers where they fit into the stringers; you made need to remove some of it to tghten the stairs.if you have acess to underneath, follow Lisa's suggestion and tighten all the shims and re-nail the risers onto the treads.
I would imagine they squeak.
if you can't get under, rip thin strips of matching pine to fit and glue only the side that touches the tread, not the riser. Push the strip down till it hits the nails, let it dry and pare it flush to the tread

[Kevin Jenness]

It's hard to tell from the photos how the stair is built. If it has housed stringers and you have access to the back side you may be able to force the risers forward to meet the treads by driving shims tighter, then screw through the back of the risers into the treads. If you can get the treads free (unlikely) you could set them farther back to meet the treads and fill the gap at the nosings. Another possibility would be to fill with a tapered shim driven in from above. In any case I would use construction adhesive at the joint. Tape up to the joint to minimize cleanup.

I don't think caulking is out of the question. Sand the back of the tread and front of riser as best you can, put blue tape at the back of the tread and just above the tread on the riser, and fill the gap to just below the tread with backer rod or some other foam that will stay in place and maintain the caulk thickness less than the joint width. Fill with polyurethane caulk like Sikaflex, tool it and remove the tape. Paint the caulk when cured. Do a test joint or two to get comfortable with the tooling step- that type of caulk is messy. I think you might get less squeaking than with a shoe molding.

[Gordon Stump]

467142

My farm house was built in 1916. The original stairs were almost identical to yours. That is they were made from construction grade fur boards. I would bet they were painted or covered with carpet.
PLAN A:
Using a small 1/8" round molding painted first to match the risers is what I recommend.


PLAN B:
I cut my treads flush with the risers and added 6/4 walnut treads scribed to fit without molding. Added tempered Masonite painted white. 5/4 oak treads are a good choice. No needed to tear anything out.

Just my $.02

[Kevin Jenness]

467142


PLAN B:
I cut my treads flush with the risers and added 6/4 walnut treads scribed to fit without molding. Added tempered Masonite painted white. 5/4 oak treads are a good choice. No needed to tear anything out.

Just my $.02

Wouldn't that mess up the first and last riser height?

[Gordon Stump]

Only the top stair is 7". The rest are 8" No animals or humans were harmed in the construction of these stairs.467148

[Jim Dwight]

I think that the reason staircases almost always have painted risers these days is it makes fixing these sort of things a lot easier.

I would stain and poly the treads first. I agree softwood is not going to stay pristine but as long as you are OK with "battle scars" they would work. After that is dry, I would caulk and paint the risers and the caulked areas. Some of your cracks are big so filler rod may be needed. Putting tape along the painted tread is a good idea so you get a clean line edge on the treads. I would use a good grade of caulk - $5-10 dollars a tube, not $1-3. The caulking may not stay pristine either but expecting no flaws when the treads are softwood doesn't seem like a reasonable expectation. Character, not perfection.

[Michael Schuch]

How about ripping some long thin strips the width of the tread with a slight downward wedge shape. Put some glue on them then hammer them into the gaps between the treads and risers. You can cut off the top of the wedge left sticking above the tread with a flush cut saw or possibly even a utility knife. Just a thought to spur some thinking more than anything.

If you have access to behind the stairs you could put some screws in from the back of the riser, through the strip into the tread to keep everything together.

When I redid my stairs I screwed the new risers to the new lower treads (with glue) before installing them as a pair, since I didn't have easy access to the back side of the stairs to add screws later. 18 years later they are still nice and tight with no movement and no noise.